Amount of Refrigerant
 

I can't seem to find how much refrigerant is in a fb A/C system. Does anyone know?

Dan it's not much. If you're wanting to know how much to add here's a tip. These old systems use a sight glass. Look on the core support, on top, left side, in front of radiator. There's a large rubber plug (or hole). Just below that is a small lense in the freon line. When filling you turn everything on and keep adding until there's no more bubbles visible traveling in the line. The bubble's are boiling freon.

Vernon

Are you recharging with R12 or R134a?

I got my cert for R12 so I can order it online. Trying to figure out how much I need to order.

Ever since I converted my Honda to r134a, I have regretted I didn't do r12 instead to compete agins't the Texas heat.

I believe it holds 28 ounces total. But that figure is from memory and Doc's getting old,lol.

what happens when you put r134a in a car that is r12

Well, if the system still has R12 in it, then you destroy the complete A/C system.

its empty

Then buy one of the correct retrofit R134a kits from your local auto parts store and your good to go. Recommend that you replace the receiver drier and get the kit with the o'rings.

Any reason NOT to use the R12A that is available? R134A can damage some systems due to the caustic action (as I understand it).

Scott

Scott, the main reason people dont use R12 is the following.
1). expensive
2). Can't dispense it themselves, have to be licensed.
As far as R134a. It's not as efffective in cooling, especially in real hot climates.
It is also more prone to leaks due to the smaller molecules. In older systems the compressors sometimes fail due to the higher pressures of R134a, not much higher but enough to end a already old compressor.
If you are going to retro to R134a the following is the best way to go about it.
1). Have the system evaucated (removeing all the old freon and oil).
2). Have the sytem flushed of all contaminents
3). Replace the receiver drier (this is a must)
4).Make sure they put it on a vacuum to make sure it holds pressure
5). Recharge with the proper amount of R134a and specified oil
6). Also make sure they put dye in it, in case there is a leak
It's either going to work great or not.
If you don't want to go thru all that then if the system is empty you can do the following.
Buy a retrofit kit to r134a with O'rings.
Recommend all accesable o'rings be changed.
Replace the receiver drier
Recharge with specified amount of freon and add additive that allows the remaining oil in the system to blend with the new oil
Remember that the amount of freon used with r134a is less then R12.

It was easy to switch from r12 to r134 on my FB. JUST MAKE SURE YOU DRAIN ALL THE R12 OIL AS MUCH AS POSSIBLE BEFORE CHANGING IT OVER TO R134...i cannot stress this enough. Yeah it may not be as cold as r12 but its alot cheaper to have. And it still keeps me cool in this HOT TEXAS HEAT!!!

Thanks and appreciate the detail! I realize original R12 is hard to get, but 12a is 5$ a can and propane or butane based in the ones I have seen. I know this gives the "real" repair shop fits but if it never gets to them, it should be okay? And the supplier provides the legal lables so that if it should make it to a refrigeration shop, they know not to mix it. I am not that impressed with R134 conversions and R12 worked really good, so I was looking for something in between that was available but also more functional.

Not to be pusher of this stuff - but this is similar to what I bought (but have not used at the Carlisle car show) http://www.duracool.com/Duracool/faqs.html

Thanks much

I have become a bit leary about using any type of propane or butane based refrigerants. While I wouldn't mind it if it lit off in the engine bay, what if there was a small leak in the evaporator there in the cab. If I hurt someone who was riding with me, I would never forgive myself.

When I converted over my honda, I put in a new compressor and just replaced the o-rings in the front part of the car. Put in a new dryer, pulled a vacuume on it and let it sit overnight. Then just used one of those refit kits and it worked fine.

Since I have my r-12 license though, I don't want a system that doesn't work as well. (license is VERY easy to get)

Most people make the mistake of thinking that R134a does not work as well as R12. If you know all the proper thing to do, it works just as well or better. Most common mistake is overcharging the system when changing over. You are only supposed to use 80 percent R134a of the system requirement. If the system calls for 2 lbs to fill, you have to remember that part of that is oil. General rule of thumb is 4 to 6 oz to every pound of freon. So, when you take 80 percent of a 2 pound system, you are left with 1 lb 9 oz. Then you subtract about 6 to 8 oz for oil, you are left with a little over a pound of freon. When you over fill a system it causes the sytem to keep shutting down to keep it from freezing the system up. I have changed a bunch of AC systems over to R134a without any problems. A good working R134a is better than a non working R12. Figure about 5 to 6 bucks for R134a for 12 oz, than figure 35 to 45 bucks a pound for R12. Then make your call.

You can find 24 oz of freon on ebay all the time for $30 thats more then a pound. :)


I have never seen a conversion work as well as the origonal. They take longer to get cool, and they don't blow as cold. I did my Honda by the book. figured out the conversion ratios, mesured in the oil, flushed the sytem, put a VERY strong vac on it, ect. My friends CRX that still has a working r12 system (same year, same model, same engine) gets colder faster, and will blow colder when it is all said and done.

I think you should stick with the system that came in the car.